Not to be harsh but this strikes me as cruel and pointless. No, neocaridina shrimp are not saltwater creatures. Not even brackish from anything I have ever heard or read. Some of the caridinas (amanos, ninjas, mandarins etc) live in salt as hatchlings but that would be logistically difficult, as some AC experimenters are finding out.
There ARE saltwater shrimp; if you wish to do such an experiment try establishing a colony of these, then your SW fish could prey on the young or weak as nature intended. To throw cherries into salt would be like throwing you into a room full of ammonia gas. Yes you might last a short while but it would be hideous.
I am the furthest thing from an animal-rights activist but this just seems wrong.